What is The Anatomy of the Knee Joint?

The knee is one of the most important yet vulnerable joints in the human body. Its mobility is more pronounced than other joints like the jaw due to the presence of a synovial fluid, which acts like a lubricant oil used in vehicles. In primates, the knee acts as a junction between the thigh and the leg and helps you carry out daily functions like running, walking, playing, etc. The structure behind this anatomical marvel is similar to door hinges, allowing the leg to bend, extend, and rotate with limited side-to-side movements.

Hi! I am Dr. Rajesh Thunuguntla, an orthopedic surgeon in Hyderabad, and today we will be talking about the basic structure of the knee joint.

What is The Anatomy of the Knee Joint?

The knee joint is a compound joint consisting of three bones connected at two junctions.

  • The Tibiofibular joint is between the femur (thigh bone) and the tibia (leg bone).
  • Patellofemoral joint: between the femur (thigh bone) and the patella (the knee cap)

The joint is encased in a joint capsule with the synovial fluid surrounding the bones.

What are the parts of a knee joint?

The knee joint is comprised of the following parts:

The knee menisci

The menisci are two articulating discs: the lateral meniscus and the medial meniscus, which partly divide the joint space. They consist of connective tissue with collagen-like fibers and protect the articulating bones from rubbing against each other.

The meniscus is flattened in the middle of the joint and is connected to the synovial membrane. It plays a significant part in shock absorption.

You need to know here that the meniscus is highly susceptible to multiple injuries and can crack, tear, or decrease in width, leading to difficulty in mobility accompanied by pain.

Dr. Rajesh Thunuguntla says that patients often approach us after an injury and immobility of the knee.

When we investigate the injury, at times it concludes with a meniscal tear which can be easily resolved with arthroscopic surgery.

You can find Dr. Rajesh Thunuguntla on clinicspots, practo, curofy, and various other social media platforms.

The knee cartilage

It is a thin elastic tissue that protects the bones and allows for easy sliding movements of the bones over each other. It is of two types; fibrous cartilage (meniscus) and hyaline cartilage. This cartilage is prone to wear and tear over the years.

Since cartilage has a less propensity for restoration, the new tissue formed is more fibrous than the original hyaline cartilage, which later develops more cracks and tears over time.

The knee ligaments

These are structures that help hold the knee joint in place and provide protection to the capsule.

They are primarily divided into intracapsular ligaments (within the capsule) and extracapsular ligaments (outside the capsule).

The intracapsular ligaments

These are two cruciate ligaments that stabilize the knee.

Anterior Cruciate Ligament ( ACL): This is a notorious ligament that is frequently injured after strenuous physical activities. The prime purpose of this ligament is to prevent exaggerated movements of the tibia too anteriorly ( to the front of the body, towards the toes).

The Posterior Cruciate Ligament: This ligament is very rarely injured, and it prevents the displacement of the tibia or the leg bone with respect to the femur, the thigh bone.

The Transverse Ligament: Remember the two menisci we spoke about? This ligament is responsible for keeping the two in place. It connects the lateral meniscus to the medial meniscus.

The extracapsular ligaments

There are five extracapsular ligaments, but three are more commonly spoken about than the rest. These three are:

The patellar ligament connects the patella or the knee cap to the tibia. It is also known as the patellar tendon and gives the patella its mechanical leverage.

The medial collateral ligament: This ligament protects the inner side of the knees from being opened or diverged due to stress applied on the outer sides of the knee.

The lateral collateral ligament: It protects the outer side from the inner forces (antagonistic to the medial collateral ligament)

And finally, the remaining two ligaments, the oblique popliteal and the arcuate popliteal are present towards the back of the knee.

Functions of the knee

The knee serves as an attachment point of many muscles via various tendons to bring about rotational, side to side, bending, and extending movements.

It is also a part of the body’s supporting framework, providing strength, mobility, and balance to the body.

Knee Joint Trauma and Dislocation

Clinically, the knee is a frequently injured and dislocated joint. This may or may not be accompanied by the feeling that a person is ‘uncertain’ about the movement or that the joint may ‘give away’. A knee injury’s primary signs and symptoms include moderate to severe pain, swelling around the knees, a locked or blocked knee.

These signs are usually seen during:

  • The strain on the joint
  • A ligament injury
  • Fractures
  • A meniscal injury
  • Wear and tear of the joint
  • The joint is also susceptible to osteoarthritis (a degenerative inflammatory disorder affecting the joint cartilage and the related bones).

Treatments for Knee joint injuries

Being an orthopedic doctor and surgeon myself, I can tell you this with a guarantee that if you find the right doctor for your injury, you can heal entirely since the treatment options are many and advanced in technology.

The technology of treatments is so advanced that a sportsperson can go back to living and playing professional-level sports.

Cost of Treatment for knee joint injuries in India

Treatment for surgeries and physiotherapies in India is significantly less than in other technologically advanced countries globally. People travel from the world over to India for orthopedic treatments because of the competitive level of treatment and cost-effectiveness and various other benefits like having a healthcare company curate your entire process for you.

The healthcare company will take care of the entire process of getting you tested, sending your reports for a consultation to the doctors, arranging your visa, tickets, inter-city travel and stay, fixing your surgery appointment, and managing your physiotherapy.

They will handhold you till you are fit to travel back home.


After explaining to you about the knee’s anatomy, I want to stress that it is important to exercise your joints regularly keep them stretched and strengthened so that even if you injure the joint, it heals faster.